Viewing archive of Tuesday, 7 September 1999
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 1999 Sep 07 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 250 Issued at 2200Z on 07 SEP 1999IA. Analysis of Solar Active Regions and Activity from 06-2100Z to 07-2100Z SOLAR ACTIVITY WAS LOW. THERE WERE TWO C-CLASS FLARES
WHICH WERE NOT OBSERVED OPTICALLY: A C1.7 AT 06/2112Z AND A C1.2 AT
07/1358Z. REGION 8690 (N13E60) HAS ROTATED MORE FULLY INTO VIEW AND
IS AN 80 MILLIONTHS D-TYPE GROUP. A NEW REGION 8691 EMERGED NEAR
S30W32 DURING THE PAST 24 HOURS. NEW REGIONS 8692 (S25E74) AND 8693
(N12E79) ROTATED INTO VIEW. BOTH OF THESE GROUPS SHOW SPOTS WITH
PENUMBRA.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
IIA. Geophysical Activity Summary 06-2100Z to 07-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS. ACE
REAL-TIME SOLAR WIND MEASUREMENTS INDICATE THE ARRIVAL OF A
HIGH-SPEED, LOW DENSITY SOLAR WIND STREAM AT ABOUT 07/0900Z. THE
HIGH VELOCITY AND FREQUENTLY OSCILLATING BZ COMPONENT OF THE
MAGNETIC FIELD RESULTED IN AN INCREASE IN ACTIVITY TO UNSETTLED TO
ACTIVE LEVELS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT THREE DAYS. THERE IS A
FAIR CHANCE FOR SOME ACTIVE PERIODS DURING THE NEXT 24 HOURS,
HOWEVER, IN RESPONSE TO THE HIGH SPEED SOLAR WIND STREAM.
III. Event Probabilities 08 SEP to 10 SEP
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 07 SEP 112 Predicted 08 SEP-10 SEP 115/115/115 90 Day Mean 07 SEP 166
V. Geomagnetic A Indices
OBSERVED AFR/AP 06 SEP 004/006 ESTIMATED AFR/AP 07 SEP 015/013 PREDICTED AFR/AP 08 SEP-10 SEP 015/013-012/013-010/010
VI. Geomagnetic Activity Probabilities 08 SEP to 10 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 25% | 15% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 35% | 20% |
| Minor storm | 20% | 15% | 10% |
| Major-severe storm | 10% | 05% | 05% |
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